Tyson deserted by both his skill and his fortune

At the age of 38, this former undisputed world heavyweight champion ought to have been enjoying a retirement buoyed by a fortune that once stood at an estimated £300million. But now his finances are as bankrupt as his ability to fight at the very highest level of this most testing of sports. He will share a square of canvas with Williams for no other reason than he needs the money.

Where did it all go wrong? Tyson believes an answer lies in a new book offering evidence that a verdict of guilty at his rape trail 12 years ago was the wrong one.

Alan Dershowitz, the acclaimed Harvard University law professor, has written "America on Trial: Inside The Legal Battles That Transformed Our Nation".

In it, Dershowitz claims to have discovered that false information was given to the jury, prosecution witnesses lied, and the evidence of three eye-witnesses who were not allowed to testify would have won the case for the defendant.

It should never be forgotten that Tyson was no saint before he was jailed. Indeed, it is generally accepted that he was always heading for a fall outside the ring just as big as his first professional defeat to Buster Douglas 17 months before Desiree Washington filed her rape complaint.

But Tyson now insists the turbulence in his later life, and the way in which he is perceived as a deeply flawed human being, might have been different had justice prevailed. "I know it's finally out in print that I didn't have a fair trial," he said. "But the problem is that people don't want to believe that I'm innocent. I knew I didn't receive a fair trail. Evidence of my innocence was available but they wouldn't accept it.

"But what am I going to do? I did not rape that girl. I'm not a rapist. But I am a black man in America and people are eager to believe that I am a rapist."

Tyson pointed to his roots, roaming those streets in New York that don't feature in any tourist guidebook, and went on: "It's a stigma.

"Most guys, from communities where I come from, are born with these stigmas. It's a really horrific thing, to punish someone who is innocent.

"There are many people in jail right now who don't belong there. Our justice system is not perfect, and I was a victim of it.

"When I was sent to prison it made me have no respect for society. It really scarred me in such a way that it's still really hard for me to overcome. I just have to keep working at it. Every day."

Tyson was working at it yesterday. And it looked very hard graft.